A study done in 1998 in-vitro showed that sperm motility (health) was reduced by urine ammonia. [1]
Beyond that, there is no clear evidence on whether urine is spermicidal, excepting the clearing through physical means of residual semen post-ejaculation.
I would assume that this is pertaining to whether it is safe for further sexual encounters post-urination as part of contraception. Barrier methods like condoms would still be advised to avoid unwanted pregnancies.
Do keep safe and protected!
Reference:
- Kim, S. C., & Kim, H. W. (1998). Effects of nitrogenous components of urine on sperm motility: an in vitro study. International journal of andrology, 21(1), 29-33.
